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HelpTest ID TBGI Thyroxine-Binding Globulin (TBG), Serum
Useful For
Cases in which total thyroid hormone levels do not correlate with the thyrometabolic status, most commonly with pregnancy or the use of contraceptive steroids
Method Name
Solid-Phase Chemiluminescent Assay
Reporting Name
Thyroxine Binding Globulin, SSpecimen Type
SerumSpecimen Required
Patient Preparation: For 12 hours before specimen collection, do not take multivitamins or dietary supplements containing biotin (vitamin B7), which is commonly found in hair, skin, and nail supplements and multivitamins.
Container/Tube:
Preferred: Red top
Acceptable: Serum gel
Specimen Volume: 0.5 mL
Specimen Minimum Volume
0.35 mL
Specimen Stability Information
| Specimen Type | Temperature | Time | Special Container |
|---|---|---|---|
| Serum | Refrigerated (preferred) | 7 days | |
| Frozen | 30 days |
Reference Values
Males: 12-26 mcg/mL
Females: 11-27 mcg/mL
For SI unit Reference Values, see https://www.mayocliniclabs.com/order-tests/si-unit-conversion.html
Day(s) Performed
Monday, Wednesday, Friday
Performing Laboratory
Mayo Clinic Laboratories in Rochester
CPT Code Information
84442
LOINC Code Information
| Test ID | Test Order Name | Order LOINC Value |
|---|---|---|
| TBGI | Thyroxine Binding Globulin, S | 3021-3 |
| Result ID | Test Result Name | Result LOINC Value |
|---|---|---|
| TBGI | Thyroxine Binding Globulin, S | 3021-3 |